The major problem faced by manufacturers of chains, pendants, necklaces and bracelets is undoubtedly that of the closure or catch structure.
In fact, losses of bracelets, necklaces and chains are without doubt due to the bad functioning of the closure structures.
The closure most commonly known and used in jewelry is constituted by a semi-ring having a tubular section to which is welded a ring through which it is solidly fixed to one of the terminals or end portions of the jewelry, and a lock acting along the interior of the tubular body urged by a spring, which lock, through a notch provided in the semi-ring, has an activating pivot protruding outwards. The lock tends to close the space existing between the ends of the semi-ring, the ring of the opposite end of the jewelry being enclosed in the interior.
This type of closure is not safe and although it is known by all jewelers and, in general, by all users, it is still being manufactured and used for the mere reason that an improved replacement has not as yet been found.
The problem exists and is serious. Therefore, closures having various forms have been designed which, although in the majority of the cases perfectly comply with their function, are expensive and extremely difficult to manufacture.